SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b355a13b76e816a0818a6914368b36c151fc3cbd84126f31e364f7f743cd06b' 
  AND token = 'anAQkr6sHLVL7Gytj4DmtqaFoJc0xi9AGJiPYf5NDfs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}